Steam boiler and method of operating the same



Dec. 1, 1931. H. WEBSTER STEAM BOILER AND METHOD OF OPERATING THE SAME Filed Feb. 12, 1925 2 Sheets-Sheet 1 ILIIi INVENTOR H. WEBSTER 1,834,261

STEAM BOILER AND METHOD OF OPERATING THE SAME Dec. 1, 1931.

2 Sheets-Sheet 2 Filed Feb. 12 1925 I N VEN TOR. M W BY Patented Dec. 1, 1931 UNITED"STATES.

PATENT OFFICE-.1

HOSEA WEBSTER, or moirroram, NEWVJERSE'Y, AssIGnoR ro THE B BcooK a wrrcox compan on BAYONNE, NEWJERSEY, A CORPORATION-OF NEW ERSE srnnivrrornna- Ann ME'rrronoFoPnRArmG THE SAME Application filedFebruary 12, 1925. Serial no. 8,625.

My present invention relates to steam boilers and their operation and particularly such boilers in which the combustion a r is preheated, before being supplied to the fuel. My invention will be best understood from the following description-andthe annexed drawings, in which Fig. 1 isa sectional elevation of one form of water tube boiler wh ch I have chosen for purposes of illustration and embodying my invention; Fig. 2 is a planview of the same, with some of the parts broken away, and Fig. 3 is a section on the line 33 of Fig. 1.

Like reference characters; indicate like parts in the different views.

her, being provided, in the illustrative arrangement, with a chain grate St0l813fi11 shown diagrammatically, air being supplied tothe upper run of the grate-through the ports 12,12, at the front end of the stoker and the ports 13, 13, at-the middle and rear end of the stoker, it being understood'that the fuel bed is carried from the left to the right in Fig. 1 I V Above-the chamber 10 is a-steani boiler which may be of any desired type but which, in the form illustrated, is of the horizontally inclined tube typehaving a set of tubes 14 30 spaced from a setof tubes 15 to form a superpbustion air enters through the duct and heater chamber in which 'is a' superheater 16, the tubes 14 and 15 being connected to uptake and downtake headers in the usual manner with steam and' water circulating tubes r 17 connecting the uptake headers wit-hthe steam and water drum 18. A baflie 19 provides up and down passes for the gases across the bank of tubes 15, the gases passing into the waste gas flue betweenthe nipples '20, from whence the gases pass back and forth through a primary air heater tothe gas exit This primary air heater, in the illustrative r form, is made up of apair of heads 22, 23 through whichextend the ends of tubes 24, baflies 25 and 26 being arranged to cause the waste gases to flow in the general direction indicated by the arrows on Fig. 1 asthey pass tothe exist 21;

The lower tubes 14 are exposed for'their Referring-to Fig. 1, 10 is a furnace cham- Ward into the second pass at therightofthe ed a secondary air heater which, in the form illustrated, is made up of plates to form alternate passages for'the air and the'furnace gases. .The plates are arranged, as shownl best inFig. 3,-to form a series-of .fulllength tothe furnace and the gases first h spaced apart ducts 27 0f rectangular crosssection, these ducts beingconnected at their right-hand ends to a flue-28 which,' inturn, is connected to theupper endszof some of'the tubes 24' of the primary air heater, the re-.

mainder of such tubes 24being connected'to a. duct 29 connected, in'turn, to a duct'30 ports 13:of the which leads to the air inlet stoker.

; Likewise the left-hand ends of theair heaterducts 27; of'thesecondary air heater be provided to control the through the several ports. I I

With the arrangement described, the compasses upward through the tubes 24, the ex teriors of which are swept by, the waste gases. Some of the air thus heated is-delivered directly to the ducts 29 and 30 and from i thence to the air inlets 13 at the rear of the furnace chamber. The remainder of this combustion air which passes throughthe tubes 24 atztheleft in Fig. 1, is carried through the secondary air heater formed of the ducts '27 where it takes up heat fromthe hot furnace gases passing from the first to the secondpass of the boiler and which, of course, are considerably hotter than the gases which sweep the tubes 24. "This por- L perature airis deliveredto the frontpart of the grate through theports 12, where the tan ion

fuel is green and where a higher temperature is desirable in order to promote combustion. This high temperature gas is not desirable at the rear of the fuel bed, particularly when certain kinds of fuels are used.

By the arrangement described, it will be seen, therefore, that the combustion air is diangular space above the tubes 15, such air heater may be placed in any other position within the boiler where it may be contacted with gases which are still passing through theboiler and which are, therefore, at a higher temperature than the gases in the waste gas flue.

t will also be understood that the form of air heaters may be widely varied and that my invention may be used with other forms of combustion apparatus and with finely pulverized or gaseous fuels as well as with solid fuels. While I have illustrated my arrangement in connection with a horizontal water tube boiler, it will also be understood that certain features of my inven .tion may be applied to other types of boilers.

I claim: 1. In combination, a. water'tube boiler and a furnace, means for directing gases from said furnace across the tubes of said boiler in a plurality of passes, an air heater located between two of the passes whereby gases pass in succession over boiler tube heating surface, then over said air'heater, and then over other boiler tube heating surface, and means for utilizing the air from said air heater for combustion purposes.

'2. The method of operating a steam boiler and its setting which consists in feeding a fuel bed into the furnace, utilizing the heat of waste furnace gases after their passage over boiler heating surfaces to heat combustion air, passing said air through one portion of: the: fuelv bed, and utilizing the heat both of Waste furnace gases after their passage over boiler heating surfaces and the heat of gases at an intermediate stage in their flow acrossboiler heating surfaces to heat combustion air and passing'the same through another portion ofthe fuel bed.

3. The method of operating a steam boiler and its setting which consists in feeding a fuel bed into the furnace, utilizing the heat of waste furnace gases after their passage over boiler heating surfaces to heat combustion air, passing said air through one portion of the fuel bed, and utilizing in succession the heat of gases from the furnace at an intermediate stage in their flow across boiler heating surfaces and the heat of Waste furnace gases after passing over additional boilor heating surfaces to heat combustion air and passing the same through another portion of the fuel bed. 7

4. In a steam boiler and its furnace, means for feeding'a fuel bed into the furnace, means for conducting heated gases from the furnace over boiler heating surfaces, a primary air heater, a secondary air heater, means for conducting said heated gases at an intermediate stage in their flow across the boiler heating surfaces into contact with said secondary air heater, means for conducting said gases after their passage across the entire boiler heating surface into contact with said primary air heater, means for conducting air from said primary air heater through one portion of the fuel bed to the furnace, and means for conducting air from said secondary air heater through another portion of said fuel bed to the furnace.

5. In a steam boiler and its furnace, means for feeding a fuel bed into the furnace, means for conducting heated gases from the furnace over boiler heating surfaces, a primary air heater, a secondary'air heater, means for conducting said heated gases at an intermediate stage in their flow across the boiler heating surfaces into contact with said secondary air heater,means for conducting said gases after their passage across the entire boiler heating surface into contact with said primary air heater, means for conducting air from said secondary air heater through one portion of the fuel bed to the furnace, and means for conducting air from said primary air heater through another portion of said fuel bed to said furnace.

6. In a stream boiler and its furnace, means for feeding a fuel bed into the furnace, means for conducting heated gases from the furnace over boiler heating surfaces, a primary air heater, a secondary air heater, means for conducting said heated gases at an intermediate stage in their flow across the boiler heating surfaces into contact with said secondary air heater, means for conducting said gases after their passage across the entire boiler heating surface into contact with said primary air heater, means forconductin g a portion of the air from said primary air heater through one portion of said fuel bed, means for conducting another portion of the air from said primary air heater-to said secondary air heater, and means for conducting air from said secondary air heater through another portion of the fuel bed.

I 7. In a steam boiler and its furnace, means for feeding a fuel bed into the furnace, means for conducting heated gases from the'furnace over boiler heating surfaces, a primary air heater, a secondary a1r heater, means for conducting said heated gases at an intermediate stage in theirffiow across the boiler heating surfaces into contact with said secondary air heater, means for conducting said gases after their passage across surface into contact with said primary air heater, means for conducting air from said primary air heater through one portion of the fuel bed to the furnace, means for conducting air from theprimary air heater to the secondary air heater, and means for conducting air from saidsecondary air heater through another portion only of said fuel bed.

8. In a steam boiler and its furnace, means for feeding a fuel bed into the furnace, means for conducting heated gases from the furnace over boiler heating surfaces, a primary air heater, ducting said heated gases at an intermediate stage in their flow across the boiler heating surfaces into contact With said secondary air heater, means for conducting said gases after their passage across further boiler heating surface into contact with said'primary air heater, means for conducting air from said primary air fuel bed to the furnace, and means for conducting air from said secondary air heater through another portion of said fuel bed to the furnace. p

9. In combination, a steam boiler and its furnace comprising a progressive feed grate, an air heater utilizing Waste heat gases from the boiler, means for conducting air from said air heater beneath one portion of the fuel bed, a second air heater for raising air toa higher temperature than that of the first air heater, and means from the second air heater beneath another portion of the fuel bed.

10. In combination, a steam boiler and its furnace comprising a progressive feed grate,

a first air heater utilizing Waste heat gases from the boiler, a second air heater, means for conductlng a portion of air from said first a1r heater through said second a1r heater and thence through one portion of the fuel bed, and means for conducting other airfrom the first air heater through another portion of said fuel bed. I

I-IOSEA WEBSTER.

the entire boiler heating a secondary air heater, means for conheater through one portion of the r for conducting the air 

